Field of the Invention
This invention relates to the technical field of welding and, more particularly, relates to a novel copper and steel composite pipe, a manufacturing method, application, and a welded structure body.
Description of the Related Art
With development of society, national energy-saving and consumption-reducing policies are promoted continuously, in every industry, resources are continuously saved and energy consumption is continuously reduced, but in the refrigeration industry, a precious metal with good plasticity and strength, namely copper, has always been used as a main raw material for production and processing. In the development course of the industry in these years, many scientists performed research work on substitution of various materials. Thus, an extremely urgent event which is conductive to the industry and the national development is to find a material which has not only a certain strength, but also plasticity and processing performance.
In products in the field of refrigeration, the connection between copper pipes often needs to be used, and flame brazing is generally adopted as the connection way. For example, an existing gas outlet pipe on a liquid storage device of a compressor is connected with a gas suction pipe of a refrigeration compressor by adopting a copper elbow made of red copper, and then the elbow made of red copper needs to consume more copper materials only for the purpose of meeting convenience and quickness in welding of a pipeline system of an air conditioner. In order to reduce the consumption of copper resources and reduce the cost, we need to research and develop a composite novel material which can meet flame brazing and simultaneously save the consumption of the copper material.
In the practices of the industry, people have adopted a process of plating copper on the surface of a steel pipe to achieve the welding effect of copper and copper. However, when such product with copper plated on steel and the copper pipe are subjected to flame brazing, the phenomenon of shedding of a plated layer after burn-in exists, and the shed plated layer can cause the serious results of blockage of the pipeline system and jamming of the compressor when entering the pipeline system of the air conditioner. In addition, the way of plating copper on the steel product is not environment-friendly and liable to produce waste gas and waste water, so that the existing application of the process is greatly restricted.
In order to solve the above problems, Chinese patent application No. 2014106032792 discloses a welding method for copper and steel and application thereof, wherein a copper pipe and a steel pipe are butt connected and welded by argon arc welding, the copper pipe and a weld seam participate in pressure bearing and vibration work in an air conditioning system. Not only the strength requirement, but also the air tightness requirement needs to be met. In the long-term using process of the product, fatigue rupture of the weld seam is liable to occur, and the actual application of a copper-steel butt welded pipe is also greatly restricted.